This archive tracks four layers. A record present in 2 of them (M41, IND) is silent in the rest, and says so.
The Horus HeresyM30–M31
[RECORD LOST]
No record for this location in The Horus Heresy.
Age of the ImperiumM32–M40
[RECORD LOST]
No record for this location in Age of the Imperium.
The 41st Millenniumpre-Rift
imperium
Segmentum Pacificus fortress
Forge world, naval headquarters of the western segmentum, and the seat of the Lords of Hydraphur, who between them run one of the Imperium's densest knots of Adeptus bureaucracy.
Era Indomituspost-Rift
imperiumImperium Sanctus
Segmentum Pacificus fortress
Still lit and still in command, but reaching into a segmentum where whole swathes stopped answering after the Night of a Thousand Rebellions.
Position
Map frame: 150, 596 in the archive's 0–1000 disk space (core at 500, 500).
Distance from the core: 363 units ≈ 38.6k light years, west of the galactic core.
Height above the disk plane: -6.6 units — invented thin-disk jitter, deterministic per record. No published source gives any location a z coordinate.
System: Hydraphur System
Books set here
1 title in the reading tracker touches this record. Titles link out to the tracker.
Every fact in this record, and where it came from. Editorial derivations say so.
segmentumhigh
wh40k.lexicanum.com/wiki/Segmentum_Pacificus 'its Segmentum Fortress is located at Hydraphur'; https://wh40k.lexicanum.com/wiki/Hydraphur infobox Segmentum = Segmentum Pacificus
derived: Segmentum Pacificus is the western/south-western segmentum; Hydraphur placed centrally within it, west and slightly south of Terra, well inside the Astronomican
book-linkhigh
wh40k.lexicanum.com/wiki/Hydraphur named in a tracked book: Avenging Son (dawn-of-fire::dof-main::1). cites that novel for the star fort Ascendant riding at anchor above the world, for the shipyard rings that circle it, and for the count of three Chaos assaults it had already survived by the early Indomitus Crusade. The world is described in the book rather than visited by it, so the link is filed at role 'mentioned'